I just bought a house and have the whole garage to build a woody in. I have a 21 foot long wall that I will be using with 8 feet to the ceiling and am looking for suggestions on shape and angle. I'm planning on an 8 foot wide wall at 45 degrees and a 4 foot wide wall at 30-35 degrees. The remaining 9 feet will be a lower angle traverse that has to be a little lower hanging to get around some garage door support arms.

I boulder V4 on plastic (which amounts to V1's in Joshua Tree, but that's a discussion for another time), so my question is....

does the setup of 8 feet at 45 degrees and 4 feet of 3-35 degrees make sense? What have people's experiences been with indoor walls and angles? Will 45 degrees not allow for a lot of diversity in climbing, or at least not at my level of climbing? Should I switch the angles and give myself more climbing area at the lower angle?

Build a wall for the skill level you want, not the skill level you have. If you have a 21 ft wide woody in your garage and you're even haldf-way dedicated to training, you'll jump past V4 pretty quickly. Unless you're a fatty or something.

I've had four different home walls in the past and I think you've got the right idea. Not sure how a 4 foot wide section will work, all mine have been 8 feet wide so I could traverse back and forth a bit. With an 8 foot ceiling, you are really limited with your vertical movement (especially on lower angles) so you will be primarily traversing or going diagonal. On the steep stuff, a small vertical kick panel is a must, otherwise you literally can't get your feet to the base of the wall (rookie mistake...live and learn). I'd make the kick panel about 1 foot high unless you have monster feet. Do not build a kick panel on anything 30* or less, it is not necessary.

Currently I have one section at 45* and another at 30* and I'm pretty happy with this set up. My next wall will have another section at 15* because I find myself climbing that angle outdoors and I'm strong enough now to use some tiny holds on it. Currently I on-sight hard .11 to easy .12 if that helps with your skill level questions. I don't regularly boulder, but V4 outdoors doesn't take me many tries.

Here are my experiences with various angles:

Roof: Pointless. This seemed like a really good idea, but it turned out to be a bust. Couldn't climb it without a spotter, and the moves lacked variety. It just wasn't nearly as fun as I thought it would be and I felt like I wasn't getting any stronger on it.

50*-55*: This was a pretty good angle, but I found the climbing to be very similar to the roof. Drop knees just aren't that thrilling for me. It was hard to find holds that weren't jugs, but still had a positive enough edge to be usable. I would not build this angle again.

45*: This is about as steep as I care to have. The angle adapts well to everything. You can do a variety of climbing movements on it and it's genuinely fun to climb.

30*: I currently have a section at this angle and really like it. You really have to keep an eye on technique or your feet will cut, but you can still use a huge variety of holds. On a 30* wall, you can use everything from pinches to slopers and it's easy to adjust difficulty by spinning the holds or changing the footholds. Maybe I just have a one-track mind, but I feel like 30* is the most versatile angle for hold variety. I set mine up with all crappy feet so you have to focus to stay on.

15*: My first wall had this angle. I really liked it at first, but then I got strong enough that pretty much every hold on it felt like a jug. I had a few holds that were super hard, but I plateaued pretty quickly on this angle. I think it's just not steep enough to see significant strength gains. Once I progressed beyond 5.10 or so it was just not hard enough. I did not have a large supply of small/tiny holds at the time so I could not increase the difficulty.

I also just bought a house and will be rebuilding my wall for the 5th time. I'm not sure about the dimensions but I will have a 45*, 30*, 15*, and possibly a tiered roof (inverted staircase is common where I climb). I'm building a 15* because of space constraints, but also because I have a pile of tiny holds now and I'm strong enough to make use of them on this angle.

A 4ft section is very small and not very usable unless it is set-up as a system wall.

Since you have a short ceiling I would consider starting with a ~35degree wall for a large section (at least 8 ft and easily 12ft) which is the angle where a lot of climbing holds work really well.

Personally I have found that if you keep the design of your wall simple and straight-forward it makes it much easier to at least get started climbing. Once you climb on it for a while you get an idea of what it needs (more steepness or more angles or smaller/larger holds). Adding volumes also are a cheap way to modify the angles on the wall.

If you can build a transition at a corner you can add some really cool moves to your wall as well. Also is there any way to extend into the ceiling?

Tipton has a lot of good advice on angles above. I would always put a little roof on the end to act as ending jugs and extend some of the moves off of the wall.

Lastly this is a good calculator to get an idea of materials and angle of your wall: visualtrig.com/ if you input 8 in the yellow box (height) and 55 in the green box for angle (this would be a 35 degree wall as shown in the upper left corner) it gives you your climbable area which is 9.8 ft. This helps you determine the amount of material you would need and give a nice visual example.

I echo everything Tipton said above, though I have way less experience. I've got a 9' tall, 33d angle wall (I was shooting for 30...) with a 15" kick board and find it excellent.

We recently added a volume in the upper middle of the wall that created a 2'x2' vertical section to add really dodgy slopers. So if you are worried that your wall is too steep to use certain types of holds, you can always selectively shallow it out with volumes.

I have a similar wall set up, one wall is 30 deg. x 8' followed by a 45deg x 6', and I would offer this info, join the two with a transition piece instead of a square corner, I did and it flows really nice moving from one angle to the other. I said that assuming you were in fact joining the two walls, if not disregard, but it is a cool idea, involves a little math making the transition piece, but its cool when done.